Rotary stop device for screening off secondary x-rays



Oct. 28, 1930. F. LEISER'I Ronny swor DEVICE FOR SCREENING OFF SECONDARY X-RAYS Filed May 2, 1927 2 Sheets-Sheet 1 INVENTOR fk/EDk/(W LE/SEE 1 ATTORNEY Oct. 28, 1930. F. LEISER 1,730,085

ROTARY STOP DEVICE FORSCREENING OFF SECONDARY X-RAYS 'Filed May-2, 1927 2 Sheets-Sheet 2 INVENTOR fiwaoR/c/v L 5155/2 ATTORN EY Patented Oct. 28, 1930 g 'UNITED, STATES: PATENT oFFic-e 4 2 rnrnnnrcn nnrsna, FBERLIN-CHARLOTTENBURG, GERMANY Romany s'ror DEVICE non sore-Belarus orrasnconnnnrx-naxs 1 npplication filed May 2, 1927, Serial No.:188,357, and in Germany May 5, 1926.

This invention relates to astop device for screening ofi the secondary X-rays by means of a device which is rotatable about an axis. In the known stops of this type the focus of 5 the tube'is positioned above the axis of rotation of thestop, while the rotary motion of the latter is obtained by means of a drive acting upon a toothed annulus at the perifery of the stop frame, whereby theangular speed of the 1Q stop is reduced. This arrangement is accompanied by the disadvantage of an increasein the time of exposure and'in that a portion of the efiective raysbecomes destroyed, thus further. increasing the time necessary for exposure.

These disadvantages are removed by the inventionaccording to which the axis of rotation of the stop is arranged parallel with the 'contral ray of the Roentgen tube. V In this way any desired speed of rotation'fof the'stop is rendered possible, so that exposures can be taken which do'not exceed the time of one half "of a second, such as they are required when taking; Roentgen photographs ofthe lungs,

heart, stomach, the intestines, and so on.

By the provision, according to'the inven tion, of strips of hard lead arranged to be retatable around their axes it is possible better to exclude the effects of straying secondary I 3 rays, 'so' that the image on the fluorescent screen appears much clearer While the R0- entgen picture shows better contrasts as will be hereinafter-more readily apparent. The employment of strips of lead for the exclu sion of the secondary rays is known per se but in the known arrangements the said strips are arranged parallel to each other and so as to be moved only to and fro about their axes.

The accompanying drawings illustrate the invention by way of an example.

Fig. 1 is a vertlcalsectlon taken on lines 1-1 of Figure 4,

Fig. 2 is-a plan view of the device,

Fig. 3 is an enlarged fragmentary section taken on the line3'3 of Figure 4,.and

Fig.4 is a horizontal section taken on the line of Figure 3, i i

In these drawin s' 1 is'an annular frame '50 preferably-made'o band iron and provided with a number (twelve for example). of

turnable leaden blades 2 arranged spoke fashion and about their pins 3, while at their opposite inner ends they" are each provided with a gear or pinion 5. All of these'gears or pinions 5 are arranged in engagement with cessively presented in avertica-l position opposite the screen (shown dotted at 7) at about I the centre ofthe same as is clearly indicated by the position of the blade 6. I

The shaft 4 of'the frame 1 is drivenat high speed as by means of an electric motor 8. A protecting screen for the patient under treat ment is shown at 9 in Fig. 2.

In the operation of the deviceas thusconstructed and arranged, the focus of the X-ray tube or anti-cathode (not shown) is approxicenter of 'mately at the center, or slightly abovethe the upper vertical radius of the circular frame 1,0r midwaybetween the axis of the frame 1 and the highest point. on its periphery, as is clearly indicated by the posiradially disposed leaden members or spokes the cooperative gears or pinions 5 the frame 1, and as each arrive at frame 1, they are positioned in edgewise relatter, so

latio'n to the X-ray tube or anti-cathode and the screen 7 at the approximatecenters of the that the primary or central rays from the tube or anti-cathode pass unob- 'structed to the plate or screen 7. However, in the vertical position of one of the leaden members or spokes 2, the oppositely disposed of the other several members or spokes 2 are being continuously turned to varying angular positions with respect thereto, and with respect toeach other by reason of the continued rotation of the frame 1, and are thus presentin from the v to secondary or straying rays, k-ray tube or anti-cathode, appretion ofthe fluorescent screen or plate 7. The

12 are turned on their axes, through the medium'of and 5" forexactly 180 during each full revolution of vertical position at the upper sideof the ciable areas of their side faces, with the result that these latter rays are absorbed.

By reason of the absorption of the secondary or straying rays aforesaid, the obtained picture on the fluorescent screen or plate 7 will be much clearer than it has hitherto been possible to produce, and furthermore, the picture, when in the form of an X-ray diagram, will show greater and more marked contrasts for the same reason. It is also to be noted that by driving the frame 1 at higher speeds, the absorption of the secondary or straying rays is accomplished in a manner that there is substantially no impairing eflects, such as, for instance, the stretching of the resultant picture out of shape or pro rtion, such as is often the case in the hereto ore known practice.

The blades 2 may consist of hard lead preferably of an appreciable transverse area or width, and may, or may not have a strengthening frame. of a more solid material which, however, must be penetrable to the X-rays. Thus it may conslst of a suitable metal; in some cases a tough lead alloy or other composition will serve the purpose and which may contain about 95 to 96 per cent of lead for example.

As shown in Figures 3 and 4, the inner ends of the radial blades 2 are journaled in a hub portion 10 and have the beveled gears 5 keyed thereon inwardly of the hub. One end of the hub is closed by a wall 10, which is engaged at the center of its inner side by one en of the driving shaft 4.

Mounted on the shaft 4, for rotation indepeendcntly thereof, is a sleeve 11 which has a veled gear 5 at one end and disposed within the open end of the hub 10 for meshing engagement with the beveled gears 5 aforesaid, a gear 12 at its other end disposed in mesh with a companion gear keyed on a countershaft 14. This countershaft 14 is jonrnaled in a bearing 15 disposed alongside a similar bearing 15 for the driving shaft 4, soasto extendparallel to the latter substantially asshown. Keyed on the driving shaft 4:, beyond the outer side of thegear 12, is another gear 16, which is arranged in mesh with a companion gear 17 keyed on the coun tershaft 14.,

N 0w, with the motor 8 con led to the free end of the driving shaft 4 an connected to a current supply line (not shown), the frame 1 will berotated with the shaft 4, when the gear'lfi on the latter will drive the counterslnft 14 through the intermeshing gear 17 Upon rotation of the countershaft 14, the ar 13. carried thereby will drive the sleeve lthrongh the intermeshing gear 12.. When the beveled gear 5 will also be rotated and will transm' motion to, the beveled gears 5 for the rotation of the spokes 3'as aforesaid. WhatI claim isjz-s 1., A rotary stop for screening off secondsecondary X-rays, comprising a circumferential ring member, a turning axle, individually turnable blades between, the said ring member and the said turning axle, a pinion at the inner end of each of the said blades in engagement with an annulus on the turning axle, and means for rotating said axle to cause a simultaneous relative rotation of said ring member and said blades.

4. A rotary stop device for screening 01f secondary X-rays directed toward a Roentgen screen comprising a turning axle, radial strips of lead turnable about their longitudinal axes and mounted I spoke-fashion upon the turning axle, and means to automaticallyturn each of the strips one-half a revolution around its longitudinal axis during one rotation of the stop device.

5. A rotary stop device for screening ofl secondary X-rays, comprising an axle, a circular framemounted in concentric relation to said axle, leaden strips journaled'radially of said axle and frame, means for rotating said axle and frame, and means operated from said axle for simultaneously rotating said leaden strips,

6. A rotary stop device for screening of secondary X-rays, oomprisin an axle mounted parallel to the path 0 the central ray emanating from a Roentgentube, a circular frame mounted in concentric relation to said axle, leaden strips journaled radially of said axle and. frame, means for rotating said axle and frame, and means operated from said axle for simultaneously rotating said leaden strips through an angle of 180 for each complete revolution of said axle and'frame.

7. A rotary stop device for screening eff secondary X-rays, comprising an annular frame, a power shaft, a hub portion fixed to said shaft, strips of screening material spaced radially within said frame and journaled at the-Opp site ends in the frame and in the hub portion, and-means forfrotating said strips simultaneously with the rotation of said frame-and said shaft.

8. A rotary stop for screening ofl secondary X-Ifiys, comprising anannular memet, a o at b e-sh ft, a h mo ntedonsaid llO shaft, individually turnable blades of screenable material. disposed between said annular member and said hub, a pinion at the inner end of each of said blades, means for im- 7 parting motion to said shaft for the rotation of said annular member and said hub and means operable from said shaft for causing a simultaneous relative rotation of said blades through said 'pinions.

9. Airotary stop for screening oflf second ary X-rays, comprising an annular member, a rotatable shaft, a hub mounted on-- said .shaft, individualrturnable blades of sereenable material disposed between said annular member and said hub, a pinion at the inner end of said blades and Within said hub, power means for imparting motion to said shaft'for the rotation of 'saidannular member and said hub, and means operable from said'shaft forcausing the simultaneous relative IOtfltlOILOf said blade'sthrough said pinions. a

In testimonywhereof I aflix my signature.

FRIEDRICH LEISER'. 

